The following abbreviations and terms are herewith defined, at least some of which are referred to within the following description of the present disclosure.
3GPP 3rd-Generation Partnership Project AGCH Access Grant Channel ASIC Application Specific Integrated Circuit BLER Block Error Rate BSS Base Station Subsystem CC Coverage Class CIoT Cellular Internet of Things CN Core Network DRX Discontinuous Receive Cycle EC-AGCHExtended Coverage Access Grant Channel EC-GSM Extended Coverage Global System for Mobile Communications EC-PCH Extended Coverage Paging Channel eDRX Extended Discontinuous Receive Cycle eNB Evolved Node B DSP Digital Signal Processor EDGE Enhanced Data rates for GSM Evolution EGPRS Enhanced General Packet Radio Service FS Feasibility Study GSM Global System for Mobile Communications GERAN GSM/EDGE Radio Access Network GPRS General Packet Radio Service HARQ Hybrid Automatic Repeat Request IE Information Element IMSI International Mobile Subscriber Identity IoT Internet of Things LC Low Complexity LTE Long-Term Evolution MCS Modulation and Coding Scheme MF Multiframe MME Mobility Management Entity MS Mobile Station MTC Machine Type Communications NB Node B PCH Paging Channel PDN Packet Data Network PDTCHPacket Data Traffic Channel P-TMSI Packet Temporary Mobile Subscriber Identity RACH Random Access Channel RAN Radio Access Network RAT Radio Access Technology SGSN Serving GPRS Support Node TBF Temporary Block Flow TDMA Time Division Multiple Access TSG Technical Specifications Group UE User Equipment WCDMA Wideband Code Division Multiple Access WiMAX Worldwide Interoperability for Microwave Access
Internet of Things (IoT) devices: The Internet of Things (IoT) is the network of physical objects or “things” embedded with electronics, software, sensors, and connectivity to enable objects to exchange data with the manufacturer, operator and/or other connected devices based on the infrastructure of the International Telecommunication Union's Global Standards Initiative. The Internet of Things allows objects to be sensed and controlled remotely across existing network infrastructure creating opportunities for more direct integration between the physical world and computer-based systems, and resulting in improved efficiency, accuracy and economic benefit. Each thing is uniquely identifiable through its embedded computing system but is able to interoperate within the existing Internet infrastructure. Experts estimate that the IoT will consist of almost 50 billion objects by 2020.
Cellular Internet of Things (IoT) devices: CIoT devices are IoT devices that establish connectivity using cellular networks.
Coverage Class (CC): At any point in time a wireless device belongs to a specific uplink/downlink coverage class that corresponds to either the legacy radio interface performance attributes that serve as the reference coverage for legacy cell planning (e.g., a Block Error Rate of 10% after a single radio block transmission on the PDTCH) or a range of radio interface performance attributes degraded compared to the reference coverage (e.g., up to 20 dB lower performance than that of the reference coverage). Coverage class determines the total number of blind transmissions to be used when transmitting/receiving radio blocks. An uplink/downlink coverage class applicable at any point in time can differ between different logical channels. Upon initiating a system access a wireless device determines the uplink/downlink coverage class applicable to the RACH/AGCH based on estimating the number of blind transmissions of a radio block needed by the BSS (radio access network node) receiver/wireless device receiver to experience a BLER (block error rate) of approximately 20%. The BSS determines the uplink/downlink coverage class to be used by a wireless device on the assigned packet channel resources based on estimating the number of blind transmissions of a radio block needed to satisfy a target BLER and considering the number of HARQ retransmissions (of a radio block) that will, on average, be needed for successful reception of a radio block using that target BLER. Note: a wireless device operating with radio interface performance attributes corresponding to the reference coverage (normal coverage) is considered to be in the best coverage class (i.e., coverage class 1) and therefore makes a single blind transmission. In this case, the wireless device may be referred to as a normal coverage wireless device. In contrast, a wireless device operating with radio interface performance attributes corresponding to an extended coverage (i.e., coverage class greater than 1) makes multiple blind transmissions. In this case, the wireless device may be referred to as an extended coverage wireless device.
eDRX: Extended Discontinuous Receive Cycle (eDRX), also labelled as eDiscontinuous reception, is a process of a wireless device disabling its ability to receive when it does not expect to receive incoming messages and enabling its ability to receive during a period of reachability when it anticipates the possibility of message reception. For eDRX to operate, the network coordinates with the wireless device regarding when instances of reachability are to occur. The wireless device will therefore wake up and enable message reception only during pre-scheduled periods of reachability. This process reduces the power consumption which extends the battery life of the wireless device and is sometimes called (deep) sleep mode.
Extended Coverage: The general principle of extended coverage is that of using blind transmissions for the control channels and for the data channels. In addition, for the data channels the use of blind transmissions assuming MCS-1 (i.e., the lowest modulation and coding scheme (MCS) supported in EGPRS today) is combined with HARQ retransmissions to realize the needed level of data transmission performance. Support for extended coverage is realized by defining different coverage classes. A different number of blind transmissions are associated with each of the coverage classes wherein extended coverage is associated with coverage classes for which multiple blind transmissions are needed (i.e., a single blind transmission is considered as the reference coverage). The number of total blind transmissions for a given coverage class can differ between different logical channels.
Nominal Paging Group: The specific set of EC-PCH blocks a device monitors once per eDRX cycle. The device determines this specific set of EC-PCH blocks using an algorithm that takes into account its IMSI, its eDRX cycle length and its downlink coverage class.
The 3GPP TSG-GERAN Ad Hoc#1 on FS_IoT_LC Tdoc GPC150055, entitled “EC-GSM—Mapping of Logical Channels onto Physical Channels”, dated Feb. 2-5, 2015 (the contents of which are incorporated herein by reference for all purposes) disclosed that the extended coverage requirements for Cellular Internet of Things (CIoT) devices can be realized on the EC-PCH by using a new 2-burst EC-PCH radio block, where the number of EC-PCH radio blocks needed to send an EC-PCH message depends on the coverage situation for the device, and thus, how many times the EC-PCH message needs to be repeated in order to reach the needed coverage extension. The number of EC-PCH radio blocks needed to send the required number of blind transmissions of an EC-PCH message ranges from 1, for devices (wireless devices) in the best (e.g., lowest) coverage class, to 32, for devices in the worst (e.g., highest) coverage class, due to the different amount of repetitions that are used when transmitting the message. Each EC-PCH message is contained within a single EC-PCH radio block, which will include space for up to 88 bits of payload. FIG. 1 (PRIOR ART) is a diagram that illustrates the EC-PCH mapping for devices (wireless devices) in the best (e.g., lowest) coverage class CC1 which requires 1 message (one 2-burst EC-PCH radio block), coverage class CC2 which requires two messages (two 2-burst EC-PCH radio blocks), coverage class CC3 which requires four messages (four 2-burst EC-PCH radio blocks), coverage class CC4 which requires eight messages (eight 2-burst EC-PCH radio blocks), coverage class CC5 which requires 16 messages (16 2-burst EC-PCH radio blocks), and coverage class CC6 which requires 32 messages (32 2-burst EC-PCH radio blocks) where CC6 is the worst (e.g., highest) coverage class.
The traditional methods for PCH bandwidth management (not EC-PCH bandwidth management) are based on the assumption that all devices (wireless devices) are of the same coverage class, which means that each nominal paging group is based on the transmission of a single PCH message that is sent using a 4-burst radio block. In addition, the traditional methods are based on the assumption that all devices (wireless devices) in the same serving cell make use of the same Discontinuous Receive (DRX) cycle length. This means that even if a device fails to read a message (e.g., a PCH or AGCH message) when the device wakes-up according to its nominal paging group, the device will have another opportunity to attempt message reception in the near future (i.e., a few seconds later). The traditional BSS therefore employs a PCH bandwidth management method that is based on these two key assumptions, neither of which is applicable to an Extended Coverage GSM (EC-GSM) system, where devices (wireless devices) may operate in different coverage classes and may make use of different eDRX cycle lengths. In the EC-GSM system, the bandwidth available for sending EC-PCH messages per the standardized 51-multiframe is limited due to the need for a BSS to also send EC-AGCH messages which also use different coverage classes. This bandwidth problem associated with EC-PCH and EC-AGCH resource management is addressed by the present disclosure.